Pneumatic burner control system



Sept. 15, 1970 c, P I 3,528,758

PNEUMATIC BURNER CONTROL SYSTEM Filed Nov. 26, 1968 4 Sheets-Sheet 1 34 36 35 T 32 4 Ll FIG.I

HIS ATTORNEYS Se t. 15, 1970 c. H. PERKINS 3,528,758

' PNEUMATIC BURNER CONTROL SYSTEM I Filed Nov 26, 1968 4 Sheets-Sheet :1

36 34" 33 w r ,L 1.

INVENTOR CHARLES H. PERKINS ms ATTORNEYS Sept. 15,1970 c. H. PERKINS 3,528,758

PNEUMATIC BURNER CONTROL SYSTEM Filed Nov. 26, 1968 4 Sheets-Sheet 4 33A 34A 35A I fl: "46A 49A -|3A 75 74 /---5lA n7 87 HT' H: BA "09 92 i a V I0? I06 89 r mvemoR 82 CHARLES H. PERKINS BY I I05 (3. ,4, 046 I HIS ATTORNEYS 3,528,758 PNEUMATIC BURNER CONTROL SYSTEM Charles H. Perkins, Richmond, Va., assignor to Robertshaw Controls Company, Richmond, Va., a corporation of Delaware Filed Nov. 26, 1968, Ser. No. 779,162

Int. Cl. F23n /02 US. Cl. 431-67 30 Claims ABSTRACT OF THE DISCLOSURE This disclosure relates to a pneumatic control system for a fuel burner means having a pneumatically operated actuator for interconnecting a fuel source to the burner means to be ignited by an electrical ignition means when a pneumatic source is interconnected to the actuator by a pneumatically operated valve means, the valve means having a pneumatically operated time delay means interconected thereto for closing the valve means if the burner means is not ignited after a predetermined time period has lapsed of which the start of the time period is initiated by the pneumatic source being interconnected to said valve means to operate the same.

This invention relates to a pneumatic control system and to an improved pneumatically operated valve means for such a system or the like.

It is well known that pneumatically operated systems have been provided for operating a domestic appliance, such as a laundry drying machine or the like.

However, one of the features of this invention is to provide outomatic time delay means in the system which will terminate the flow of fuel to the burner means of the apparatus if the burner means is not ignited within a predetermined time period.

Another featue of this invention is to provide a flame sensing means which overrides the time delay means so that when a flame exists at the burner means the time delay means can not terminate the flow of fuel to the burner means after the lapse of the aforementioned time period.

One embodiment of this invention for accomplishing the above features comprises a pneumatically operated valve means which is adapted to interconnect a pneumatic source to a pneumatically operated actuator when the pneumatic source is interconnected to the valve means, the thus actuated actuator interconnects a fuel source to the burner means to be ignited by an electrical ignition means of the system. However, the pneumatically operated valve means has a time delay chamber so constructed and arranged that the same is also interconnected to the pneumatic source through a restriction so that when the time delay chamber reaches a certain pnuematic condition, the time delay chamber causes the valve means to close to deactuate the actuator and thereby terminate the flow of fuel to the burner means. The valve means also has a flame sensor which when sensing a flame at the burner means overrides the operation of the time delay chamber, the flame sensor comprising a rod and tube arrangement.

Accordingly, one of the objects of this invention is to provide an improved pneumatic control system having one or more of the novel features set forth above or hereinafter shown or described.

Another object of this invention is to provide an improved pneumatically operated valve means for such a system or the like.

Other objects, uses and advantages of this invention will be apparent as this description proceeds with reference to the accompanying drawings forming a part thereof and wherein:

nited States Patent 0 FIG. 1 is a schematic view, partially in cross section, ilustrating one pneumatic control system of this invention, the system being in its off condition.

FIG. 2 is a view similar to FIG. 1 except that the system is in its on condition.

FIG. 3 is a schematic view, partially in cross section, illustrating another pneumatic control system of this invention, the system being in its off condition.

FIG. 4 is a view similar to FIG. 3 except that the system is in its on condition.

FIG. 5 is a fragmentary view of the system of FIG. 4 and illustrates the pneumatically operated valve means in another operating position thereof.

While the various features of this invention are hereinafter described and illustrated as being particularly adapted to control a laundry drying machine of the fuel burning variety, it is to be understood that the various features of this invention can be utilized singly or in any combination thereof to provide control means for other types of apparatus as desired.

Therefore, this invention is not to be limited to only the embodiments illustrated in the drawing because the drawings are merely utilized to illustrate one of the wide variety of uses of this invention.

Referring now to FIGS. 1 and 2, an improved pneumatic control system of this invention is generally indicated by the reference numeral 10 and comprises a fuel source conduit means 11 adapted to be interconnected to a burner means 12 of a laundry dryer or the like by a pneumatically operated actuator 13, the actuator 13 comprising a housing means 14 having a valve seat 15 between the fuel source 11 and burner means 12. The valve seat 15 is adapted to be opened and closed by a valve member 16 interconnected to a flexible diaphragm 17 so as to be movable therewith, the flexible diaphragm cooperating with the housing means 14 to define a chamber 18 therewith that is fluidly interconnected to a conduit means 19. A compression spring 20 is disposed in the chamber 18 and tends to urge the flexible diaphragm downwardly so as to close the valve member 16 against the valve seat 15.

In this manner, the valve member 16 remains in its closed position to prevent the fuel source from being interconnected to the burner means 12. However, when a vacuum source is interconnected to the chamber 18 in a manner hereinafter described so as to evacuate the chamber 18, the resulting pressure differential across the diaphragm 17 causes the diaphragm 17 to move upwardly against the force of the spring 20 to open the valve seat 15 and keep the valve seat 15 open as long as the chamber 18 remains evacuated.

A pneumatically operated valve means 21 of this invention forms part of the system 10 and comprises a housing means 22 carrying two flexible diaphragms 23 and 24 cooperating therewith to define two chambers 25 and 26. The chamber 25 is interconnected to a chamber 27 by a valve seat 28 that is normally closed by a valve member 29 that is urged against the valve seat 28 by a compression spring 39.

The chamber 27 is fluidly interconnected to the conduit 19 while the chamber 25 is fluidly interconnected to a conduit 31 that leads to a bacuum source 32, the vacuum source 32 comprising an electrically operated vacuum pump adapted to be placed across a pair of power source leads L and L by a pair of electrical switches 33 and 34. The switches 33 and 34 are in a lead 35 leading from the power source lead L to a terminal 36 of the pump 32 while the power source lead L is interconnected to another terminal 37 of the pump 32 by a lead 38.

The switch 33 can be a centrifugal switch on the blower motor and drum motor (not shown) of the dryer apparatus so that when these motors are not running the electrical circuit to the vacuum pump 32 is broken. The switch 34 can be a switch on the timer of the apparatus to terminate the cycle of operation of the apparatus. Alternately, the switch 33 could be a high limit safety switch or the like. In any event, when the apparatus is turned on, the switches 34 and 37 will be automatically closed so the vacuum pump 32 will continuously operate during substantially the entire heating cycle of the apparatus.

An electrical switch 39 is carried by the housing means 22 and has an operating plunger 40 which when in its in position as illustrated in FIG. 1 connects a pair of terminals 41 and 42 thereof together, the plunger 40 when in its out position as illustrated in FIG. 2 electrically disconnects the terminal 42 for a purpose hereinafter described.

A lead 43 interconnects the lead 35 intermediate the pump 36 and switches 33 and 34 to the terminal 41 of the switch 39. A lead 44 interconnects the terminal 42 to one side 45 of an ignition coil 46 disposed adjacent the burner means 12 to ignite the same in a manner hereinafter described. The other side 47 of the ignition coil 46 is interconnected by a lead 48 to the lead 38.

A tube 49 of a flame sensor 50 is interconnected to the housing means 22 and carries a rod 51 having its lower end 52 fastened to the closed end 53 of the tube 49 so as to move in unison therewith. The rod 51 passes through a bore 54 in the valve member 29 so as to form a restriction passage between the chamber 27 and the chamber 25 when the valve member 29 is in its closed position. The tube 49 cooperates with the housing means 22 to define the chamber 27 therewith, the tube 49 having an orfice 55 for interconnecting the atmosphere to the chamber 27 for a purpose hereinafter described.

The housing means 22 also defines a restricted passage 56 between the vacuum source conduit 31 and the chamber 25.

A tubular plunger 57 is carried by the flexible diaphragm 23 and has an end 58 for abutting against the valve member 29, the rod 51 passing through a bore 59 in the plunger 57 and diaphragm 23 and cooperating therewith to define a restricted passage between the chamber 25 and the chamber 26. However, the plunger 57 has a plurality of spaced abutments 60 on the upper end thereof surrounding the bore 59 adapted to be engaged by a disc member 61 carried by the rod 51.

The plunger 57 is loosely telescoped within a tubular extension 62 of the housing means 22 that fluidly interconnects the valve seat 28 with the chamber 25. A compression spring 63 is disposed in the chamber 25 about the tubular extension 62 and normally urges the flexible diaphragm 23 upwardly against the stop disc 61 of the rod 51.

Another compression spring 64 is disposed in the chamber 26 about the rod 51 and normally urges the flexible diaphragm 24 upwardly to hold the plunger 40 of the switch 39 in its in position whereby the terminals 41 and 42 are electrically interconnected together.

A conduit 65 interconnects the chamber 25 to temperature control device 66 that is adapted to interconnect the conduit 65 to the atmosphere if the temperature of the dryer exceeds a high limit. Alternately or in addition, the device 66 could be a door operated device that will interconnect the conduit 65 to the atmosphere if the dryer door is opened and will close the conduit 65 from the atmosphere when the dryer door is closed.

However, as illustrated, if the device 66 is a temperature device the same can comprise a housing 67 having a valve seat 68 adapted to interconnect the conduit 65 to the atmosphere. A valve member 69 is carried on the end of a rod 70 that is carried by a tube 71 so that when the tube expands relative to the rod upon a sensing of an excess temperature, the valve member 69 is moved away from the valve seat 68. However, as long as the temperature being sensed is below the high limit, the tube 71 maintains the valve member 69 in its closed position against the valve seat 68. A passage 72 is formed through the diaphragm 23 to interconnect the chambers 25 and 26. However, a one-way check valve 73 closes the passage 72 as long as the chambers 25 and 26 are at atmospheric condition or the chamber 25 has a lower pressure than chamber 26.

Therefore, it can be seen that the system 10 and pneumatically operated valve means 21 of this invention can be formed of a relatively few parts adapted to be assembled together in a simple and economical manner to provide a unique control system that operates in a manner now to be described.

When the apparatus is in the oh. position of FIG. 1, the actuator 13 is in its deactuated condition as the atmosphere enters the orifice 55, chamber 27 and conduit 19 to maintain the chamber 18 at atmospheric condition so that the valve member 16 is held in its closed position by the spring 20 whereby no fuel can flow to the burner means 12. However, when the dryer is turned on and the centrifugal switch 33 on the blower and drum and the timer switch 34 are closed so that the vacuum pump 32 is placed across the power source leads L and L and begins to operate to evacuate the chamber 25 through the restricted passageway 56. As the chamber 25 is evacuated, the resulting pressure differential across the diaphragm 23 causes the diaphragm 23 to move downwardly in opposition to the force of the spring 63 and engage and move downwardly the valve member 29 away from the valve seat 28 as illustrated in FIG. 2. In this manner, the chamber 25 is now interconnected to the chamber 27 whereby the vacuum pump 32 is interconnected to the actuator 13 to actuate the same and open the valve seat 15 so that fuel can now issue from the burner means '12.

Simultaneously, the closing of the switches 33 and 34 places the ignition coil 46 across the power source leads L and L as the plunger 40 of the switch 39 is in its in position as illustrated in FIG. 1 whereby the heated coil 46 ignites the fuel issuing from the burner means 12. The ignited burner means 12 is now sensed by the sensor 50 whereby the heated tube 49 expands downwardly and carries the rod 51 therewith so that the stop disc 61 is also moved down to prevent the valve member 29 from closing and also to maintain the restricted bore 59 closed from the chamber 25 as the end of the plunger 57 is seated against the valve member However, vacuum leaks between the restricted bores 54 and 59 from the chamber 27 to the chamber 26 at a controlled rate so that after a predetermined time period, a suflicient leakage of vacuum occurs in the time delay chamber 26 so that the resultant pressure differential across the diaphragm 24 causes the diaphragm 24 to move downwardly in opposition to the force of the compression spring 64 in the manner illustrated in FIG. 2 so that the switch plunger 40 moves outwardly to electrically disconnect the terminals 41 and 42 from each other and thereby disconnect the ignition coil 46 from the power source leads L and L The control system thus remains in the condition illustrated in FIG. 2 to continuously operate the burner means 12 until the timer opens the switch 34 and terminates the operation of the burner means 12 because with the loss of the vacuum pump 32, the system 10 bleeds down to atmospheric condition by means of the orifice 55 whereby the actuator 13 is deactuated and closes the valve member 16 against the valve seat 15 so that fuel cannot flow to the burner means 12.

However, if during start up of the system 10, the burner means 12 fails to ignite upon the opening of the valve member 29, the tube 49 does not elongate and the vacuum leaking through restricted passages 54 and 59 will subsequently cause an equalization of vacuum conditions in the chambers 25 and 26 whereby there is no longer a pressure differential across the diphragm 23 and the spring 63 will move the diaphragm 23 upwardly carrying the plunger 57 therewith so as to close the valve member 29 against the valve seat 28 and open the end 58 of the plunger 57 to the chamber 25. The closing of the valve member 29 deactuates the actuator 13 so as to close the valve seat 15.

However, since a vacuum now exists in the chamber 26, switch 39 is opened and the igniter 46 is thus deenergized.

The system must then be restarted by venting the vacuum therein by opening the dryer door whereby the V conduit 65 is opened to the atmosphere and the chamber 25 can return to atmospheric condition. With chamber 25 at atmospheric condition and the chamber 26 at subatmospheric condition, the check valve 73 opens and allows the chamber 25 to rapidly equalize the pressure in chamber 26 therewith so that the diaphragm 24 moves upwardly to close switch 39 to energize the igniter 46 for a subsequent try at ignition of the burner means 12.

If it is desired to maintain the igniter 46 in an off condition until the dryer door is again closed, this may be done by a series connected normally opened electrical switch which is operated to the on condition by the closing of the dryer door, such switch being in the lead 35.

Therefore, it can be seen that the system 10 and pneumatically operated valve means 21 of this invention operate in a unique manner to assure that the burner means 12 will be properly ignited within a predetermined time period after initial start up.

Another pneumatically operated control system of this invention is generally indicated by the reference numeral 10A in FIGS. 3-5 and parts thereof that are similar to the system 10 previously described are indicated by like reference numerals followed by the reference letter A whereby it can be seen that the pneumatically operated actuator 13A controls the flow of fuel from the fuel source conduit 11A tothe burner means 12A in the manner previously described for the actuator 13.

Similarly, the system 10A includes the vacuum pump 32A, leads 35A and 38A and switches 33A and 34A that functions in the manner previously described. The ignition coil 46A has its one side 47A interconnected by a lead 48A to the lead 38A. However, the other side A of the coil 46A is interconnected by a lead 74 to a vacuum operated switch 75 that electrically interconnects the lead 74 to a lead 76 when the switch is at atmospheric conditions, the lead 76, in turn, being interconnected to a terminal 77 of an electrical switch 78 interconnected to a housing means 79 of another pneumatically operated valve means 80 of this invention.

Another terminal 81 of the switch 78 is interconnected by a lead 82 to the lead 35A, the terminals 77 and 81 comprising switch blades having contacts 83 and 84 on the free ends thereof adapted to contact each and complete a circuit through the switch 78 in a manner hereinafter described. 7

The housing means 79 is divided into three stacked chambers 85, 86, and 87, the chambers 85 and 86 being separated by a fixed wall 88 and the chambers 86 and 87 being separated by a flexible diaphragm 89 carrying a plunger 90 that passes in a sealing manner through a bore 91 in the fixed wall 88. A compression spring 92 is disposed in the chamber 86 and tends to normally urge the diaphragm 89 to the up position illustrated in FIG. 3.

A flame sensor A for the valve means 80 comprises a tube 49A carrying a rod 51A, the tube 49A cooperating with the housing means 79 to define the chamber 85. The rod 51A has a stop disc 93 on the lower end thereof that is adapted to engage and hold a switch plunger 94 in its down position in FIG. 3 in opposition to force of a compression spring 95 so as to place the contacts 83 and 84 in electrical contact with each other when the sensor 50A fails to sense a flame at the burner means 12A. However, when a flame exists at the burner means 12A, the tube 49A elongates and carries the rod 51A therewith so that the plunger 94 can move upwardly to open the con tacts 83 and 84 as illustrated in FIG. 4.

A lever 96 is suspended in the chamber 85 of the valve means 80 by a tension spring 102 attached at point 97 to the lever 96, the lever having a slot 98 in the right end 99 thereof that reecives the rod 51A and is engageable against the top of the stop disc 93. A compression spring 100 is also disposed in the chamber 85 and bears against the underside of the left hand end 101 of the lever 96 to tend to pivot the lever in a clockwise direction as will be apparent hereinafter.

The conduit 19A interconnects the chamber 85 with the actuator 13A and has an extension 103 to interconnect the conduit 19A with the atmosphere when a vacuum dump valve member 104 is moved away from the extension 103. A conduit means 105 leads from the inlet side of the vacuum pump 32A to the chamber 86 and to an extension 106 that will interconnect the conduit 105 to the atmosphere when a dump valve 107 is moved away from the extension 106. The conduit means 105 also leads to a restricted passage 108 in the housing means 79 that leads to the chamber 85. The conduit means 105 has a restriction 109 therein with the restriction 109 interconnecting the conduit 105 to the time delay chamber 87.

Another passage 110 is formed in the housing means 79 so as to interconnect the atmosphere to the chamber '85, the passages 108 and 110 respectively having valve seats 111 and 112 adapted to be opened and closed by ball valve members 113 and 114 that are respectively urged against the lever 96 on opposite sides of the tension spring point 97 by compression springs 115 and 116. The force of the springs 100, 102, 115 and 116- and the location of their respective action on the lever 96 is so arranged that the lever 96 is pivoted to and maintained in the position illustrated in FIG. 3 by the spring 100 when theflame sensor 50A is in the condition illustrated in FIG. 3 as the sensor 50A does not sense a flame at the burner means 12A. Thus, the lever 96 permits the spring 116 to open the ball member 114 away from the valve seat 112 to interconnect the atmosphere with the chamber 85 whereas the lever 96 holds the ball member 113 against the valve seat 111 to disconnect the chamber 85 from the vacuum source conduit 105, the stop disc 93 being in the position of FIG. 3 to permit the lever 96 to open the passage 110 and close the passage 108 when the sensor 50A senses that no flame exists at the burner means 12A.

However, when the diaphragm 89 is moved downwardly as in FIG. 4, the plunger 90 pivots the lever 96 in a counterclockwise direction to cause the ball member 114 to close the passage 110 and the ball member 113 to open the passage 108, the end 99 of the lever 96 moving upwardly relative to the rod 51A because of the slot 98 thereof. Subsequently, when the sensor 50A senses a flame at the burner means 12A, the tube 49A expands upwardly carrying the rod 51A therewith so that the stop disc 93 is in the position of FIG. 4' to hold the lever 96 in that position even when the diaphragm 89 moves upwardly in the manner illustrated in FIG. 5 for a purpose hereinafter described.

Thus, it can be seen that the system 10A and valve means 80 can be for-med from a relatively few parts that can be simply and economically assembled together to operate in a manner now to be described.

When the switches 33A and 34A are closed in the mannenr previously described to initiate the operation of the system 10A, the vacuum pump 32A is started and the ignition coil 46A is energized because the pneumatically operated switch 75 is closed as the chamber 87 is at atmospheric condition at the contacts 83 and 84 are held against each other because the sensor 50A does not sense a flame at the burner means 12A. The now energized vacuum pump 32A creates a vacuum in chamber 86 and because the vacuum pump 32A is being interconnected to the chamber 87 at a controlled rate by the restriction 109, a resulting pressure differential is created across the diaphragm 89 to move the diaphragm 89 and plunger 90 downwardly from the position of FIG. 3 to the position of FIG. 4 in opposition to the force of the compression springs 92 and 100 to pivot the lever 96 in a counterclockwise direction to close the passage 110 and open the passage 10'8 whereby the vacuum source 32A is now interconnected to chamber 85 and, thus, through conduit 19A to the actuator 13A. Thus, the actuated actuator 13A interconnects the fuel source 11A to the burner means 12A so that the issuing fuel from the burner means 12A is ignited by the energized coil 46A. The flames now existing at the burner means 12A are sensed by the sensor 50A to cause the tube 49A to elongate and move the rod 51A and stop 93 thereof to the position of FIG. 4 whereby the igniter 46A is deenergized.

The restriction 109 subsequently permits the vacuum pump 32A to create a vacuum in the time delay chamber 87 that is equal to the vacuum in the chamber 86 whereby the resulting decrease is pressure differential across the diaphragm 89 permits the spring 92 to move the diaphragm 89 upwardly as illustrated in FIG. 5. However, the lever 96 remains in the position of FIG. 4 because of the elongated sensor 50A whereby the actuator 13A remains connected to the vacuum source 32A to maintain a continuous flow of fuel to the burner means 12A until the cycle of operation is terminated by the timer operated switch 34A deenergizing the vacuum pump 32A and the system 10A bleeds down to atmospheric condition by means of a controlled bleed orifice 117 in the tube 49A that leads to the atmosphere whereby the actuator 13A is deactuated to disconnect the fuel source 11A from the burner means 12A.

If, however, during initial start up of the system 10A, the burner means 12A is not ignited for any reason, the subsequent equalizing of vacuum conditions in the chambers '86 and 87 causes the diaphragm 89 and plunger 90 to move upwardly as in FIG. and the lever 96' will pivot therewith in clockwise direction by the force of the compression spring 100 to open the vent passage 110 and close the vacuum source passage 108 because the tube 49A has not expanded whereby the actuator 13A will be deactuated to terminate the flow of fuel to the burner means 12A.

At this time, the system A must be recycled to cause a new attempt at ignition of the burner means 12A by causing a temporary dumping of the vacuum in the chamber 86. This may be done by operating the dump valve member 107 or by cutting off the pump 32A or by a combination of both.

For example dump valves 104 and 107 and switch 33A could be operated to their opened positions by opening the dryer door whereby the vacuum in chamber 86 will be dumped and the valves 104 and 107 and switch 33A will again be closed upon the subsequent closing of the dryer door whereby the system 10A will again attempt an ignition of the burner means 12A in the manner previously described.

If it is desired to turn off the igniter in the event of a failure to ignite the burner means 12A, this can be accomplished by interconnecting the vacuum switch 75 to the chamber 87 by a conduit 118. Thus, after failure to achieve ignition at the burner means 12A and the vacuum in the time delay chamber 87 equalizes with the vacuum in the chamber 86 to cause deactuation of the actuator 13A, such vacuum in the chamber 87 causes the switch 75 to open and thus deenergize the igniter 46A until the system is reset in the manner previously described to dump the vacuum in the chambers 86 and 87 whereby the switch 75 returns to atmospheric condition and closes.

Thus, it can be seen that the system 10A of this invention is fail safe in the event of any orifice plugging or excessive leakage of valves, or damaged connecting tubing either by pinching or leaking. The only exception to this would be if the one tube or conduit 19A to the actuator 13A were pinched absolutely dead tight after a vacuum had been pulled on the actuator 13A to actuate the same. However, a small leak orifice tothe atmosphere in the housing of the actuator 13A would remedy this situation.

Therefore, it can be seen that this invention not only provides unique systems for pneumatically controlling an apparatus, but also this invention provided unique pneumatically operated valve means for such a system or the like.

What is claimed is:

1. In a fuel control system having a pneumatically operated actuator for interconnecting a source of fuel to a burner means when a pneumatic source is interconnected to said actuator, the improvement comprising a pneumatically operated valve means disposed between said actuator and said pneumatic source, said valve means being moved to an open position when said pneumatic source is interconnected thereto to actuate said actuator so that said fuel source is interconnected to said burner means to be ignited, said valve means having pneumatically operated time delay means operatively interconnected thereto which will close said valve means if said burner means is not ignited within a predetermined time period that is initiated when said pneumatic source is first interconnected to said pneumatically operated valve means and to said pneumatically operated time delay means.

2. In a fuel control system as set forth in claim 1, said valve means having a flame sensor operatively interconnected thereto that prevents said time delay means from closing said valve means after the lapse of said predetermined time period if said flame sensor senses a flame at said burner means.

3. In a fuel control system as set forth in claim 2, flame sensor comprising a rod and tube arrangement.

4. In a fuel control system as set forth in claim 3, rod carrying a valve member on the free end thereof.

5. In a fuel control system as set forth in claim 3, rod carrying a lever pivoting means on the free thereof.

6. In a fuel control system as set forth in claim 1, said valve means having a housing means provided with two chambers, one of said chambers causing said valve means to move to an open position thereof when said one chamber is interconnected to said pneumatic source, the other chamber providing said time delay means which has its time period initially started when said other chamber is initially interconnected to said pneumatic source.

7. In a fuel control system as set forth in claim 6, passage defining means interconnecting said pneumatic source to said chambers and to each other.

8. In a fuel control system as set forth in claim 7, restriction means in said passage defining means intermediate said two chambers and defining part of said time delay means.

9. In a fuel control system as set forth in claim 6, said housing means having flexible diaphragm means separating said two chambers from each other.

10. In a fuel control system as set forth in claim 9, a second flexible diaphragm means carried by said housing means and cooperating with said first-named diaphragm means to define said other chamber therebetween.

11. In a fuel control system as set forth in claim 10, an electrical switch carried by said housing means and being operated by said second diaphragm means, said electrical switch controlling electrical ignition means for said burner means.

12. In a fuel control system as set forth in claim 1, said valve means having an electrical switch interconnected thereto for operating an electrical ignition means for said burner means.

said

said

said end 13. In a fuel control system as set forth in claim 12, said pneumatically operated time delay means being operatively interconnected to said switch for operating the same.

14. In a fuel control system as set forth in claim 12, said valve means having a flame sensor operatively interconnected thereto that prevents said time delay means from closing said valve means after the lapse of said predetermined time period if said flame sensor senses a flame at said burner means, said flame sensor being operatively interconnected to said switch for operating the same.

15. In a fuel control system as set forth in claim 1, said valve means comprising a housing means having valve seat interconnecting said pneumatic source to said actuator, said housing means carrying a movable valve member for opening and closing said valve seat, said housing means carrying a flexible diaphragm operatively interconnected to said valve member for controlling movement thereof and defining a chamber with said housing means, said pneumatic source being interconnected to said chamber by passage defining means.

16. A pneumatically operated valve means for interconnecting a pneumatic source to a pneumatically operated actuator for interconnecting a source of fuel to a burner means, said valve means being moved to an open position when said pneumatic source is interconnected thereto to actuate said actuator, said valve means having a housing means, said housing means having pneumatically operated time delay means operatively interconnected to said valve means to close said valve means if said burner means is not ignited within a predetermined time period that is initiated when said pneumatic source is first interconnected to said pneumatically operated valve means and to said pneumatically operated time delay means.

17. A pneumatically operated valve means as set forth in claim 16, said housing means carrying a flame sensor operatively interconnected to said valve means that is adapted to prevent said time delay means from closing said valve means after the lapse of said predetermined time period if said flame sensor senses a flame at said burner means.

18. A pneumatically operated valve means as set forth in claim 17 wherein said flame sensor comprises a rod and tube arrangement.

19. A pneumatically operated valve means as set forth in claim 18 wherein said rod carries a valve member on the free end thereof.

20. A pneumatically operated valve means as set forth in claim 18 wherein said rod carries a lever pivoting means on the free end thereof.

21. A pneumatically operated valve means as set forth in claim 16, said housing means having two chambers, one of said chambers causing said valve means to move to an open position thereof when said one chamber is interconnected to said pneumatic source, the other chamber providing said time delay means which has its time period initially started when said other chamber is initially interconnected to said pneumatic source.

22. A pneumatically operated valve means as set forth in claim 21 wherein said housing mean has passage defining means for interconnecting said pneumatic source to said chambers and to each other.

23. A pneumatically operated valve means as set forth in claim 22 wherein restriction means is said passage means intermediate said two chambers and defining part of said time delay means.

24. A pneumatically operated valve means as set forth in claim 22 wherein said housing means has a flexible diaphragm means separating said two chambers from each other.

25. A pneumatically operated valve means as set forth in claim 24 wherein said housing means has a second flexible diaphragm means cooperating with said first-named diaphragm means to define said other chamber therebetween.

26. A pneumatically operated valve means as set forth in claim 25 wherein an electrical switch is carried by said housing means and is operatively interconnected to said second diaphragm means to be operated thereby, said electrical switch being adapted to control electrical ignition means for said burner means.

27. A pneumatically operated valve means as set forth in claim 16 wherein an electrical switch is carried by said housing means and is adapted to control an electrical ignition means for said burner means.

28. A pneumatically operated valve means as set forth in claim 27 wherein said pneumatically operated time delay means is operatively interconnected to said switch for operating the same.

29. A pneumatically operated valve means as set forth in claim 28 wherein said housing means has a flame sensor operatively interconnected thereto that prevents said time delay means for closing said valve means after the lapse of said predetermined time period if said flame sensor senses a flame at said burner means, said flame sensor being operatively interconnected to said switch for operating the same.

30. A pneumatically operated valve means as set forth in claim 16 wherein said housing means has a valve seat for interconnecting said pneumatic source to said actuator, said housing means having a movable valve member for opening and closing said valve seat, said housing means carrying a flexible diaphragm operatively interconnected to said valve member for controlling movement thereof and defining a chamber with said housing means, said housing means having passage defining means for interconnecting said pneumatic source to said chamber.

References Cited UNITED STATES PATENTS 3,153,440 10/1964 Baumanns 431-67 3,295,586 1/1967 McCarty et al. 137-65 X 3,384,071 5/1968 Body et al. 126-273 X EDWARD G. FAVORS, Primary Examiner 'U.S. Cl. X.'R. 137-65 

